We introduced North America to its first silica cat litter, Litter Pearls and Ultra Pearls, and it has been a tremendous product since their introduction. Like all the other fine products from Ultra Pet , Litter Pearls and Ultra Pearls are made from high quality ingredients that deliver superior results. Ultra Pearls are different because they are semi-spherical limiting tracking outside of the litter box and are soft on the cats’ paws.